


An exorcist, under investigation

by heyhay13



Series: An exorcist - Crossovers [2]
Category: Ao no Exorcist | Blue Exorcist, Kuroshitsuji | Black Butler
Genre: Crossover
Language: English
Status: In-Progress
Published: 2014-08-15
Updated: 2015-06-20
Packaged: 2018-02-13 05:46:59
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 5
Words: 3,489
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2139312
Author URL: https://archiveofourown.org/users/heyhay13/pseuds/heyhay13
Summary: <blockquote class="userstuff">
              <p>The True Cross Order is sent to investigate supernatural activities in London leading Rin, Yukio and the other Exwires to a grand ball at the Phantomhive manor. What they come to discover is more complex than any of them ever expected.</p>
            </blockquote>





	1. A new mission

**Author's Note:**

> This piece takes place after my "An exorcist in a tailcoat" series (may have some references to it).
> 
> Also, it is putting Blue Exorcist in the same time period as Black Butler. So all the same things took place in the Blue Exorcist time line, just earlier.

                The youngest of the exorcists of the True Cross Order entered the office to find the director waiting with his usual smirk. A small green hamster crawled around the brim of Director Mephisto’s hat as he greeted the boy.

                “Welcome Yukio,” the demon said, reaching a hand up to pluck the rodent off his hat and set him free on his desk as the exorcist came over to him.

                “You wanted to see me, sir?” Yukio replied.

                “I have a new assignment I want you and your Exwires to look into,” he told him, picking up a file off the desk and handing it too him. “There is some demonic activity of interest in London we have been asked to look into,” he continued to explain as Yukio opened the folder.

                “London? Isn’t that a little out of our range sir?” Yukio immediately asked but the director just smirked.

                “That branch is busy with another case and requested some assistance. I thought it would be a good opportunity for the Exwires so I took them up on the offer. Now then, notice the records of supernatural activity. What do you see?” Mephisto asked, waiting as he looked over the first few pages.

                “It has… gone down? But that doesn’t make sense, why does it need investigation if it has gone down sir?” he asked, looking back up.

                “Because we do not know why. England is a popular area for demons and we have records of some possibly very powerful ones in fact. The problem is that in the last two years, that activity has gone down and we need to know why. The order suspects another supernatural force in motion, possibly another demon has overthrown the previous one or an unidentified exorcist has taken care of it. Either way, we want to know more.”

                “Alright, so what do you want us to do? All of London is a bit much don’t you think?” Yukio asked him.

                “Yes, of course. That is why you will start by going to a party!” the director said with a chuckle, only laughing more as he saw Yukio’s face when he said it. “This isn’t just any party either! It is the ball of the young Lord Phantomhive! You will be going undercover as lords and ladies to investigate. The ball is sure to attract all kinds of nobles from the London area and we know the Phantomhive family is involved in much of the underworld side of the city, so it is the perfect opportunity find a few clues on suspicious activity.”

                “And… how long to we have before this event…?” Yukio asked, adjusting his glasses as he tried to comprehend why the director had thought this would be a good task for the Exwires.

                “Three days!” Mephisto cheered, then tossed a key to Yukio. “This will lead you to a nearby inn. You will go there tomorrow to be fitted by a tailor and rent a coach for the event. And be sure to give those Exwires a few lessons in proper manners!” he said with a smile.

                “Yes sir” Yukio replied, taking the key and the folder and started to walk out.

                “Oh, and Yukio, Shura will be joining you on this assignment.” Mephisto added, smirking as the exorcist immediately looked irritated.

                “Of course, sir.” Yukio muttered before walking out.

                This was going to be challenging… to say the least.


	2. Preparations for a party

**Summary for the Chapter:**

> The Exwires start preparing for their new mission

“Shit shit shit shit!!!” Rin muttered to himself as he ran down the halls of cram school. He skidded to a stop as he finally reached the door and he burst in. “Sorry I’m late!” He apologized quickly, rushing to his seat as he could feel the irritated glare on him from his twin. He plopped down at his desk, tail swishing as he looked up to Yukio and gave an apologetic smile. His brother sighed but let it go as he turned to the rest of the class.

                “Now that all of you are here, I have an announcement to make. We have been selected for a mission.” Yukio told them and the class instantly cheered. Rin’s attention perked at the mention of going out in the field. “There is a mysterious change in the demonic activity and we are being sent to investigate. The director thought it would be a good opportunity for you Exwires to get some experience in undercover investigation work.” He explained and they others only got more excited as he said “undercover”.

                “So we get to be like, spies??” Shima asked, the pink-haired student looking overly excited.

                “Yes, but this will take a lot of work. I hope all of you have been paying attention in your English class because we are traveling to London, England for this mission.” He said. “We will be going in three days and we will be starting by going to a party.”

                “Ah yeah!!! This sounds awesome!!” Shima cheered again, looking to Rin and high-fiving him.

                “This is not just a party!” Yukio snapped quickly, regretting his word choice. “We will be going to a _ball_ and we have three days to make the lot of you worthy lords and ladies worthy of attending such an event at Lord Phantomhive’s manor.” Shiemi made an excited noise while most of the rest of them groaned, losing some of their eagerness now.

                “Today we will be focusing completely on etiquette and acting to prepare for the undercover work and tomorrow we will be traveling to England to get you all to look the part,” Yukio explained. “Now I want-” he started, but was stopped as the door slammed open.

                “Yukioooo! You started debriefing without me??” Shura cried as she waltzed in, putting on a horrible fake pouty face.

                “Class, I forgot to mention this, but Miss Shura will be joining us on this assignment.” Yukio sighed as his eyebrow twitched in irritation.

                “Hell ya I am! Now where were you?” she asked with a wide smirk.

                “About to start etiquette, which you need to work on too!” he snapped at her.

                “Let’s get this party started then!” the exorcist cheered, sitting down in a desk next to Rin and put her feet up on the desk. Yukio shock his head and looked to Rin next to her. His twin could instantly tell what was on the professor’s mind.

                This would be a long three days.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                Two days the class was busy preparing in London. Yukio was busy trying to do last minute lessons to the students between the tailoring sessions. Rin chuckled as he saw Bon come out of his “makeover”, seeing the other Exwire had a completely new look. His blonde stripe was gone, just like Shima’s pink hair and Shura’s two tones. Bon’s hair was slicked back and his piercings removed.

                “Did we have to change my hair…?” he whined as he walked out.

                “Don’t worry Bon! We can change it right back! I think you look good!” Shiemi cheered sweetly and Rin smiled, admiring how she always knew what to say to make people feel better. Bon blushed and thanked her as the tailor came out and called Rin inside. He walked over, a little nervous, but followed the man.

                “Now let’s try this on!” he said after looking him over and taking some measurements. The man’s assistant was holding a formal suit and tail coat in traditional black. Once Rin had the foreign garments on, the tail grimaced, touching his pointed ears. The young lady assisting him then handed him a top hat which was promptly stuffed on Rin’s head. “There! Perfect!” he cheered with a smile. “You look just as handsome as any young lord” he said, admiring his work before sending Rin out. He went back out to his friends and they looked surprised.

                “You clean up well Rin!” Shima said after a moment, smiling as the others agreed.

                Yukio soon came out as well, also in a full suit. He looked over his class and smiled lightly.

                “Well, at least you all look the part.” He said then checked his watch. “Now we have a ball to get to!” he said, opening the door and the students eagerly went out to the carriage waiting. Yukio lead them out while Rin hung back. He made sure all his friends were out when he noticed someone missing.

                “SHUMA! We have to go! Come on!” he called. The changing room door slammed open and he was shocked to see the exorcist.

                “I’ve never worn so much clothing in my life.” She hissed bitterly, looking positively livid as she walked out, a little shaky on the heels. She was dressed in a dark red and black gown with her now blonde only hair in a complete up-do. Rin smiled at her.

                “You look great, now come on before my brother gets mad at both of us!” He said then lead his mentor out to the ride.  


	3. A dance with death

The group of young Exwires were all amazed as the carriage came up to the mansion. The house was amazingly decorated and looked as if it were glowing in the setting sun. Music filtered out from inside and each carriage that came to the front revealed all kinds of lords in ladies dressed to the nines. As their own carriage came to a stop, Rin looked over to his friends nervously.

                “Alright everyone, you know your role, just do what we practiced.” Yukio told them before the door opened up. Rin followed his brother out before turning and helping Shiemi out.

                “Ready to go?” Shiemi said sweetly and Rin gave her a slight smile as he offered his arm. They walked up the steps together. The next coach had the rest of the Exwires, who soon followed them in. Rin was too caught up in amazement to really notice what the others were doing as the grand doors lead the largest party the boy had ever seen.

                “Welcome to the Phantomhive manor, I do hope you enjoy your evening.” An elegantly dressed old butler greeted them. Shiemi thanked him excitedly before leading Rin down to the ballroom floor.

                “Remember, we need to be monitoring for supernatural activity. Talk to as many people as you can to dig for information” Yukio whispered to his brother. Rin nodded then turned to Shiemi.

“Let’s start by splitting up?” he suggested. She agreed then they went out towards opposite ends of the dance floor. Rin didn’t get very far though before someone bumped into him and nearly knocked him over.

                “Oh! I’m so sorry! I wasn’t paying attention to where I was go- oh hello there,” the person said, helping Rin straighten back up. “Now aren’t you a handsome young thing” the stranger said and the exwired looked up to see a woman with long red hair, a extravagant red gown and green eyes that seemed to look straight to his soul. It took Rin a moment, but he then realized that the stranger wasn’t actually a woman at all.

                “It’s alright.” He said, looking up at the… guy?

                “My name is Grell Sutcliffe! And you are?” the stranger asked.

                “Lord Rin Okumura.” He replied.

                “I don’t think I’ve seen you before Rin. You must not be from around here.” Grell told him, leaning in close to him with a smile. Rin noticed is sharp teeth and was instantly more interested as he saw that this guy didn’t look exactly human.

                “My brother and I are visiting from Japan.” He told him.

                “Oohh! Exotic! How exciting” he purred, leaning in closer to the shorter male.

                “Um, would you care to dance Miss Sutcliffe?” he asked nervously, using “miss” since this boy was clearly dressed up as a girl for a reason. He instantly smiled and took Rin’s hand.

                “You sure know how to please a lady, but please, call me Grell!” He chimed before dragging Rin into the crowd of dancers. The exwire wasn’t sure if this was a good idea, but this man seemed to stand out in the crowd and could know something.

                “So… Grell, what brings you here tonight?” Rin asked him as they started dancing, which was a slight challenge with the height difference.

                “Business sadly… I’m busy working away at a party… sad isn’t it?” he whined.

                “Sounds awful! What are you working on?” Rin asked, actually smiling as he started to feel more comfortable doing this.

                “I’m investigating some _things_ ” Grell said with a devilish smirk.

                “Oh really? What kinds of things?” he asked.

                “Nosy boy!” Grell teased, but he couldn’t help but brag a little. “If you must know, someone here has been arrested for human trafficking before…” he said with a smirk and Rin’s eyes widened.

                “What??” he asked, but just then Shiemi came up to him, another young blonde girl at her side.

                “Rin! This is Lady Elizabeth, Lord Phantomhive’s fiancée,” She introduced as Rin stopped dancing.

                “Hello my lady,” he said with a slight bow and the girl giggled.

                “Please, call me Lizzy!” she said sweetly.

                “She wants to introduce us to the Earl, we must go say hello!” Shiemi said happily and Rin was actually really impressed with how she had gotten them the chance to actually talk to the young lord.

                “It looks like I will take my leave then,” Grell said, stepping away. “Though, I do hope we meet again Rin~!” He purred before going off into the crowd again. Rin turned to the girls again and smiled.

                “Well it would be rude not to say hello to the host, please lead the way my Lady.” Rin said to Lizzy. She smiled then led them off, talking the whole time about the party and all the important people there. When she brought them to the base of the grand stair case, Rin was surprised as she ran over and took the hand of a boy shorter than him. He looked over to them with his single, bright blue eye before walking over, head held high.

                “Hello, my name is Lord Ciel Phantiomhive, it is a pleasure to make your acquaintance.” The boy said, holding his hand out to Rin. He shook it, looking over him then noticed the man behind him. The moment Rin saw the butler dressed in black, he felt his blood run cold.

                “T-The pleasure is all mine.” He said nervously, beginning to sense that there was a lot more going on in this manor than they ever could have expected.

 

 


	4. More at play

**Summary for the Chapter:**

> Ciel knows more is going on when his investigation is interrupted by more than one uninvited guest.

“T-The pleasure is all mine.” The black haired boy said as he shook Ciel’s hand. The young Earl could tell from just a glance that he did not belong here. As soon as their little chat ended as Lizzy took over talking to them once more, Ciel excused himself, motioning for Sebastian to follow.

                “It appears we have a few uninvited guests my lord.” His butler said and Ciel nodded.

                “That Okumura boy clearly is not noble. He looks too nervous and scripted, so what is he doing here?” Ciel said, looking back out over the party guests. “And the Reapers are here.” He said with distaste as he spotted the shinigami dressed in blood red standing next to the reaper Will.

                “It appears that this investigation is becoming more complicated than we thought.” Sebastian commented, also scanning the crowd. The party was supposed to be a set up in their current investigation. There had been another series of kidnappings and the Viscount Druitt was their main suspect again. The party was a set up to try and lure him, or the kidnapper, out as many of the victims had been taken from similar events. The arrival of these foreigners and the reapers meant that there was much more at play here.

                “I want to know what they are doing here.” Ciel said, turning to the demon. “Find out what they want. They may be the true kidnappers, but I suspect they are here for something else. They seem to be investigating something. Find out what it is and who they work for, this is an order.” He said and Sebastian bowed down before him.

                “Yes, my lord.” The demon said, then stood and turned to the crowd. He paused for a moment though and Ciel was about to ask when Sebastian turned back to him. “Young master, the Viscount has left the ballroom.” He informed him.

                “What?!” Ciel snapped, quickly looking over the crowd for the blonde man but didn’t see him anywhere.

                “It also appears that Lady Elizabeth and her new friend are missing as well.” Sebastian added and Ciel growled, pissed that the arrival of their uninvited guests had distracted him from his mission.

                “Find them. Now.” Ciel ordered, watching as his eyes flashed magenta and his pupils narrowed before he looked over the party.

                “He is leaving in a carriage right now, and both of the girls are with him. They appear to be unconscious. They are headed back towards the city, likely to the Viscount’s local address.” He said, eyes locked on the coach that Ciel couldn’t see.

                “The reapers are on the move as well… come on. We have to get there before them.” Ciel said, turning to Sebastian.

                “Yes, my lord.” He replied before lifting the young boy up. In a moment they were outside and the next they were soaring through the night air towards the city. They landed gracefully in front of the grand manor only a few minutes after the Viscount had arrived. Once he was back on the ground, Ciel turned to the house

                “Let’s begin.”

 

 


	5. An unexpected ally

**Notes for the Chapter:**

> I apologize for how long it took me to update!! I lost my inspiration for this story but recently I got a bunch of messages asking me to continue it. That, and I just rewatched Blue Exorcist so I finally go the motivation and ideas to continue it! Thank you so much for your encouragement!

“What do you mean Shiemi’s missing??” Yukio snapped at his brother.

                “I was doing what you said! Talking to people but went I looked over Shiemi was gone. I saw her talking to a tall, fancy blond guy and that Lizzy girl last, but now I can’t find her!” Rin said, panicked as he was scared for their friend.

                “Well, well it sounds like you’re little friend might be in trouble, yes?” Rin and Yukio both jumped and spun around at the voice. Behind them stood the redheaded reaper, smiling down at them.

                “G-Grell!” Rin stammered, not sure what to say.

                “Please, miss there is nothing to be concerned about. I am sure my brother has just lost track of his date among all the guests.” Yukio said quickly, not wanting to expose themselves or get anyone else involved. Rin was silently thankful for his brother’s ability to keep his calm in this situation.

                “I do wish that was the case, but Rin you remember what I told you before?” Grell said and Rin’s eyes widened.

                “You said someone here is involved in human trafficking.” He said quickly and Yukio tensed. “You don’t think Shiemi-?” He started but Grell cut him off.

                “That someone is a tall, fancy blond man named the Viscount Druitt who’s favorite prey is young ladies.” Grell told them.

                “Why… why are you telling us this?” Rin asked quickly.

                “Well I do believe he just left in the company of your friend and the Earl’s young fiancé.” Grell told them.

                “Grell! What have I said about getting involved?” Another voice hissed as Will came up beside the redhead. “Besides, we have work to do.” He said irritably as he pushed up his glasses.

                “Aw Will! I was just helping the little exorcists out a bit!” Grell whined and both boys froze.

                “How did you-?!” The twins said at once and Grell smirked.

                “Oh I know a great deal of things, now are you going to come after the Viscount with us?” Grell asked and Rin nodded. Will sighed, looking annoyed at Grell but he didn’t protest against bringing the exorcists, with what was to come, it could save him having to work overtime if they were there. On their way out, the passed Bon and the others.

                “Where are you going?” Bon asked quickly as they followed him out. “Who are they??”

                “Shiemi has been kidnapped, we’re going after her and they’re going to help.” Rin said quickly as they rushed to their carriage. While the others climbed on though, Grell and Will stopped.

                “Come on!” Rin told them quickly and Grell laughed.

                “Just follow us okay boys?” He said before looking down at his dress. “Such a waste of a perfect outfit.” He sighed and in a fast motion he removed the dress and was now in his usual attire, though he was still in tall heels and pulled on a long red coat. What stunned the exorcists the most though was the chainsaw Grell now held in his hands. “Come along!” Grell said before turning to the road. He and Will both jumped and went soaring down towards the town. For a moment, they were all stunned, trying to figure out who and what these strangers were.

                “Let’s go!” Rin said suddenly, picking up the reins of the carriage and took off, racing after the reapers.


End file.
